KR102223979B1 - Fluid bath cooled energy storage system - Google Patents

Abstract

The energy storage system includes a container enclosing an array of battery cells and having a fluid surrounding the array of battery cells. The system may include a cooling system to increase the transfer of heat energy from the battery cells. The system may include an outer fluid loop configured to transport fluid out of the container through the heat exchanger. The system may also include a wall configured to be connected to the enclosure and having a communication port carrying electrical signals through the wall.

Description

Fluid bath cooling energy storage system {FLUID BATH COOLED ENERGY STORAGE SYSTEM}

Cross-reference of related applications

This application claims the advantage of US Provisional Patent Application No. 61/781,406 filed March 14, 2013, which is incorporated herein by reference in its entirety.

Vehicles incorporating an electric motor require high voltage energy storage systems to properly drive the motor. High voltages sometimes require multiple battery cells to be electrically connected in series with each other. Battery storage cells generate heat due to a chemical reaction within the cells when they are charged or discharged as heat generation is a by-product of electricity generation. When multiple battery cells are accommodated in close proximity, the heat generated by each cell can increase throughout the system, causing problems such as cell thermal runaway that can destroy the storage system. . Additionally, for optimal energy efficiency, uniform temperatures of the battery cells must be maintained. Therefore, it is necessary and beneficial for such a system to include means for cooling the battery cells.

An additional problem with high voltage battery cells is the risk of fire from corona or arc flashes or ignition of vented gases that occur if open circuits. In addition, salt fog and debris can cause corrosion and unwanted leakage current paths or short circuits to be present in the storage system.

Current designs use air cooling or liquid cooling assembled into manifolds and piping to remove excess heat from the battery cells. Air cooling does not prevent salt fog or other corrosive substances from reaching the battery cells even when the filter is used. Liquid cooling that is assembled into manifolds and piping can leak, leaving a leakage current path present in the storage system. Additionally, this design adds volume to the storage system, which causes problems with space-efficient original designs or hybrid retrofit applications.

Another design incorporates a non-conductive fluid inside the casing that houses the battery cells. In some cases, the fluid can be made to move within the casing, which increases heat energy transfer. This design can reduce problems with arc flash, corona and corrosion. However, such a design is difficult to repair as the fluid must be drained or otherwise received when servicing battery cells or other components. In addition, this design still cannot provide adequate thermal energy transfer to avoid cell thermal runaway.

Therefore, there is a need for improvement in this field.

The energy storage system described herein addresses the above problems as well as other problems. The energy storage system includes a battery cell and a container enclosing a fluid surrounding the battery cell with electrical insulating and thermally conductive properties, which reduce or eliminate problems with arc flash, corona, and corrosion. The container can be hermetically sealed to further alleviate these problems. The energy storage system may include a cooling system capable of causing the transfer of thermal energy from the fluid to the exterior of the container. The use of such a cooling system can greatly increase the rate of heat transfer from the battery cells, which in turn can reduce or eliminate the possibility of cell thermal runaway or otherwise overheating of the battery cells. The energy storage system may include a recirculation pump that causes circulation of the fluid. The energy storage system can include an outer fluid loop that carries fluid out of the container, and a recirculation pump can flow fluid through the outer fluid loop. The recirculation pump can be located in the container or along the outer fluid loop. The energy storage system may include a heat exchanger located on the outer fluid loop, which heat exchanger causes the transfer of thermal energy from the fluid to the outside of the container. The cooling system may include an evaporator located within the container or located along an outer fluid loop. Cooling fins may be attached to the outside of the container to further increase heat energy transfer from the battery cells to the outside of the container.

In other examples, the energy storage system includes a wall having a communication port configured to carry electrical signals through the wall while maintaining a sealed environment of the container. An enclosure having terminals and a controller is configured to mate with a container and a communication port to transmit and receive electrical signals. The enclosure and communication ports enable the components of the energy storage system to be easily separated from the fluid for increased durability while maintaining the sealed environment of the container.

Further forms, objects, features, aspects, benefits, advantages, and examples of the present invention will become apparent from the detailed description and the drawings provided herein.

1 is a schematic diagram of an energy storage system.
2 is a schematic diagram of an alternative example of an energy storage system.
3 is a schematic diagram of an alternative example of an energy storage system.

For the purpose of facilitating an understanding of the principles of the present invention, reference is now made to the embodiments illustrated in the drawings, and specific expressions will be used to describe the same. Nevertheless, it will be understood that no limitation of the scope of the invention is intended. Any alternatives and further modifications in the described embodiments and any further application of the principles of the invention as described herein are contemplated as commonly occurring to those skilled in the art to which the invention pertains. It will be apparent to those skilled in the art that some features not related to the present invention have not been shown for clarity.

For the detailed description and claims, it should be noted that the singular term includes the plural unless otherwise stated. By way of example, reference to “device” includes one or more such devices and equivalents thereof. It should also be noted that directional terms such as "top", "bottom", "top", "bottom" and the like are used solely for the reader's convenience to aid the reader's understanding of the illustrated embodiments, and in any way such The use of the directional terminology is not intended to limit the described, illustrated, and/or claimed features to a particular orientation and/or orientation.

In the following description, reference numerals have been arranged to help quickly check the drawings in which various components are first illustrated. In particular, the drawing in which the element first appears is typically indicated by the leftmost digit in the corresponding reference number. For example, an element identified by a serial number of "100" appears first in FIG. 1, and an element identified by a serial number of "200" appears first in FIG. 2.

1 shows an exemplary diagram of an energy storage system 100. Although the energy storage system 100 is suitable for use in hybrid vehicles as well as other types of vehicles or transportation systems, it is contemplated that various aspects of the energy storage system 100 may be incorporated into other environments. In the context of a hybrid vehicle, the energy storage system 100 receives electrical energy generated by an electric motor/generator (not shown). The energy storage system 100 also supplies electrical energy to the electric motor/generator and to the inverter, DC-DC converter, or other components in turn. The energy storage system 100 communicates with the electric motor/generator and other components through the use of high voltage wiring.

The energy storage system 100 includes a container 102 that provides structural support for the energy storage system 100. The container 102 includes a number of walls 104, a floor (not shown) and a cover (not shown). As shown in FIG. 1, the container 102 forms a rectangular shape comprising four walls 104, and one wall 104 is formed as a bulk head 106. The walls 104 provide structural support for the container 102. The seals between the walls 104, the cover, and the floor create an airtight and fluidically sealed environment within the container 102. The walls 104, floor, and cover are mated to each other and are sealed to allow the container 102 to be filled with fluid 108 while not allowing any fluid 108 to leak through the seals. Seals may be any seals, such as welded or polymeric seals, that are generally known in the art and are capable of withstanding volatile temperature variations and ranges. A pressure relief valve (not shown) is included in at least one wall 104. In the case of an increase in the internal pressure above the target threshold, the pressure relief valve enables gas or fluid to be released from within the container and prevents cracking or other failure of the container 102. The pressure relief valve works in only one direction and does not allow outside air or water to enter the inside of the enclosure. Although the container 102 shown in FIG. 1 is shown as a generally rectangular shape, the illustration is for illustrative purposes only, and the container 102 may be formed in any of a variety of shapes.

The walls 104 have an inner surface 110 and an outer surface 112. The distance between the inner surface 110 and the outer surface 112 defines the thickness of the walls 104. The walls 104 are preferably made of a material having beneficial thermal properties, such as aluminum, steel, magnesium, or other form of metal or non-metal. Preferably, the material has high thermal conductivity so that any thermal energy generated in the container 102 can be quickly transferred from the inner surface 110 to the outer surface 112. Additionally, the walls 104 may be constructed of a material that is heat resistant and structurally sound when subjected to extreme temperature changes or when exposed to extreme temperature ranges.

The battery cell arrays 114 are located within the container 102. The battery cell arrays 114 are essentially a linked group of electrochemical batteries to store the energy generated by the electric motor/generator and quickly supply it back to the electric motor/generator. Although the illustrated example shows a container 102 comprising two battery cell arrays 114, the energy storage system 100 may include more or less battery cell arrays 114 than that shown. The battery cell arrays 114 comprise individual battery cells that can be chained to each other in series or parallel as required by a particular system (not shown). The battery cell arrays 114 are connected by a data link 116 which provides an electrical connection and facilitates communication between the various battery cell arrays 114. Battery cell arrays 114 are electrically connected to bulk head 106 via data link 118. The data links 118 and 116 may include any electrical connectors and signal carriers known in the art and suitable for carrying an electrical signal in a variable temperature environment. Electrical connectors and signal carriers that are part of the data links 118 and 116 may include physical components protruding from or fastened to the battery cell arrays 114.

Individual battery cells of the battery cell arrays 114 seal the internal components of the battery cells so that no fluid or air can penetrate the battery walls and damage the battery cells, correspondingly the internal integrity of the battery cell arrays 114. Including battery walls. Battery walls are generally made of a material such as aluminum or other metal or non-metal having high thermal conductivity so that the thermal energy generated within the battery cells can be quickly transferred to the outer surface of the battery walls.

The container 102 contains a fluid 108 located inside the container 102. The fluid 108 is located within the container 102, the inner surface 110 of the container 102, the battery walls, the bulk head 106, electrical connectors and signal carriers that are part of the data links 118, 116, and Direct contact with any of the other components. Because the interior of the container 102 is sealed, the fluid 108 cannot escape from within the container 102. Fluid 108 is sufficient to cover and fluidly surround battery cell arrays 114 and data links 118 and 116. In this way, oxygen is effectively removed from around the battery cell arrays 114 and data links 118, 116, and no flame is present around the battery cell arrays 114 and data links 118, 116. Does not or cannot be created. This reduces or eliminates the risk of igniting any vented gas. If an open circuit occurs within the energy storage system 100 it also reduces the likelihood of arc flash or corona. In addition, the submersion of the battery cell arrays 114 and data links 118, 116 removes oxygen from around the electrical component, which reduces the likelihood of moisture or oxygen-induced corrosion. Additionally, fluid 108 electrically insulates battery cells better than air gaps. Fluid 108 is a fluid that is preferably electrically insulating so that there is no risk of a short circuit in the energy storage system when electrical components are immersed in fluid 108. Additionally, the fluid 108 is a fluid that has a balance of high electrical insulation properties and high thermal conductivity for increased thermal energy transfer rates within the container 102. Such fluids are known in the art such as certain types of oils, such as transformer oils or transmission oils, for example. Additionally, fluid 108 may be a phase change material with increased heat absorption capability during a phase change. The container 102 may be substantially filled with fluid 108 and leaves little or no air space inside the container 102. Alternatively, the container 102 is configured such that the battery cell arrays 114 and data links 118, 116 are immersed in the fluid 108 even while the container 102 is not fully filled with the fluid 108. Can be, whereby the battery cell arrays 114 and the data links 118, 116 do not reach the lid of the container 102.

A recirculation pump 120 is located within the container 102. Recirculation pump 120 circulates fluid 108 throughout container 102. The recirculation pump 120 is shown in FIG. 1 as being located at the proximal end of the container 102. However, the description is for illustrative purposes only, and the recirculation pump may be located in other parts of the container 102. The recirculation pump 120 may be a positive displacement pump, which converts external power into the motion of the pump mechanism and flows fluid through the inlet and outlet. Alternatively, recirculation pump 120 may be a basic propeller that converts rotational motion into forced fluid flow or any of a variety of mechanisms suitable for causing fluid circulation within container 102. The recirculation pump 120 may also cause fluid motion and may be any of a variety of suitable mechanical devices known in the art. The recirculation pump 120 circulates the fluid 108 throughout the interior of the container 102 such that the fluid 108 circulates at a generally uniform circulation rate along the fluid flow path 122 throughout the interior of the container 102. (The fluid flow path 122 is generally shown by dashed arrows in Fig. 1 as well as in Figs. 2 and 3). The recirculation pump 120 is electrically connected to the bulk head 106 via a data link 118.

The fluid flow path 122 as shown in FIG. 1 generally follows a line running through a central passage between two battery cell arrays 114 from the front end of the container 102 toward the rear end of the container. The fluid flow path 122 diverges and runs on either side of the container to move around or through the battery cell arrays 114, from which the flow path is again in the container 102 near the inner surface 110. Proceed towards the front end of. Because the battery cell arrays 114 are composed of individual battery cells, the fluid flow path 122 can flow between individual battery cells such that the fluid 108 passes directly across the battery cell walls.

A number of cooling fins 124 are attached to the outer surface 112 of one or more walls 104. In the example of FIG. 1, cooling fins 124 are attached to two of the outer surfaces 112. However, the energy storage system 100 may include one or more walls 104 as well as cooling fins 124 arranged in various configurations located outside the floor or cover of the container 102. The cooling fins 124 are generally configured as an array of substantially flat planar structures. The cooling fins 124 are positioned parallel to each other and are attached at a right angle to the outer surface 112. The cooling fins 124 have a large amount of surface area to maximize the conductive heat energy transfer rate. The cooling fins 124 are formed of a material having high thermal conductivity, such as aluminum or other metal or non-metal. The use of cooling fins to increase the rate of convective or conductive heat energy transfer is known to those skilled in the art.

One of the container walls 104 is configured as a bulk head 106. The bulk head 106 maintains a hermetically sealed environment inside the container 102 while providing an electrical communication link between the inside of the container 102 and the outside of the container 102. The mating enclosure 126 is configured to mate with the container 102, in particular the bulk head 106. The mating enclosure 126 is configured to be attachable to the bulk head 106 and to be easily removable for maintenance or configuration tasks. The mating enclosure 126 may be attached to the bulk head 106 using bolts, levers, latches, or any of a variety of attachment mechanisms. The mating enclosure 126 houses various controllers 128, terminals 130, and fuses 132. The terminals 130 are the electrical energy storage system 100 and the electrical energy storage system 100, such as, for example, an electric motor/generator, an inverter, a DC-DC converter, or other components that may be part of an electric hybrid vehicle. ) Enables data connection and high power links between external components.

The enclosure 126 includes one or more receptacles 134 configured to receive one or more communication ports 136 located in the bulk head 106. The receiving portions 134 receive terminals 130 configured to mate with corresponding terminals located at the communication ports 136. When paired with each other, the receptacles 134 and the communication ports 136 create a data connection, whereby electrical signals and power are transmitted from inside the container 102 to the enclosure 126 or through the enclosure. I can. The mating enclosure 126 can be separated from the container 102 so that no fluid can escape from the container 102 during repair of any component located within the mating enclosure 126, while It is configured so as not to impair the sealed integrity of the interior of the container 102. When the mating enclosure 126 is removed from the container 102, the bulk head 106 leaves and maintains the sealed integrity of the interior of the container 102.

Receptacles 134 are shown in FIG. 1 as recesses of the enclosure 126. Communication ports 136 are shown in FIG. 1 as protrusions of bulk head 106. However, this description is merely exemplary and the configuration of the receptacles 134 and the communication ports 136 may be any of a variety of suitable configurations. Additionally, although three receptacles 134 and three communication ports 136 are shown in FIG. 1, these are only exemplary, and more or less receptacles 134 and communication ports 136 are shown. Can be integrated in the energy storage system 100. Communication ports 136 receive data links 118 and the data links terminate at a contact configured to connect in a mating contact at the receiving portions 134. In this manner, communication ports 136 directly connect data links 118 to controller 128 through terminals 130 of enclosure 126. Communication ports 136 are located around the data links 118 and terminals 130 to maintain the sealed integrity of the interior of the container 102 so that no fluid 108 can pass through the communication ports 136. Provide seals. Seals of terminals 130 and communication ports 136 are known to those skilled in the art and are sealed with any of a variety of terminals 130 suitable for variable temperature environments such as compression seals, O-rings, or polymer seals, for example. It can be goodies. The bulk head 106 may be coated with an insulating layer to reduce temperature variations of the communication ports 136 or may be made of an insulating material such as ceramic, for example.

One or more sensors 138 are located within the container 102. Although FIG. 1 shows a single sensor 138 for illustrative purposes, in practice the energy storage system 100 may include any number of sensors 138 located in various configurations within the container 102. Sensors 138 may be connected to battery cell arrays 114 or otherwise disposed within container 102. The sensors 138 may be any of a number of sensors for measuring a physical parameter within the container 102, such as the temperature of the battery cells, the temperature of the walls 104, or the temperature of the fluid. Additionally, the sensors 138 may be pressure sensors, liquid level sensors, and battery cell voltage sensors. The sensors 138 are electrically connected to the bulk head 106 via data links 118.

The mating enclosure 126 includes a controller 128 that acts as a battery measurement system. The controller 128 controls data transfer and power flow between the energy storage system 100 and various components of the electrical energy storage system 100 as well as external components such as an electric motor/generator, inverter, or DC-DC. Includes control commands to enable. Additionally, the controller may be located in various locations outside the mating enclosure 126 and may be electrically connected outside the mating enclosure 126. The controller receives information from the sensors 138 and controls the recirculation pump 120 or other component of the energy storage system 100 to adjust the temperature of the battery cells or other parameters in the container 102. The sensors 138 are configured to provide information to the controller 128 located in the mating enclosure 126. Controller 128 receives information from sensors 138 via data links 118. The controller 128 also communicates with the recirculation pump 120 and other components located in the container 102 via data links 118. The controller 128 controls the operation of the recirculation pump 120 and any other components located within the energy storage system 100. The controller 128 can receive information such as voltage and capacity information from the battery cell arrays 114 via data links 118 and pass this information to an electric motor/generator or other component that is part of a hybrid vehicle. have. Controller 128 also enables power transfer to and from battery cell arrays 114 via data links 118.

In an alternative embodiment, mating enclosure 126 may be fixedly attached to container 102. In this way, mating enclosure 126 becomes inseparable from container 102. Instead, mating enclosure 126 and various controllers 128, terminals 130, and fuses 132 are made serviceable and configurable while attached to container 102. Alternatively, mating enclosure 126 may be an internal component of container 102 such that mating enclosure and container 102 share or partially share at least one wall 104. In this way, the mating enclosure 126 and the compartment containing the fluid bath may be two compartments of the same container.

It will be foreseen by those skilled in the art that high voltage battery cells chained together in close proximity can generate a significant amount of thermal energy during charging or discharging. Thermal energy accumulated in the battery cell arrays 114 conducts thermal energy transfer to individual battery cells. In this way, during operation of the energy storage system 100, at various times, if no thermal energy management system is ready, the battery cells and battery walls reach a fairly high temperature and catastrophic failure to the system. Can cause. For example, cell thermal runaway, which can occur when raising the temperature of a battery cell, can trigger a chemical reaction that results in the release of additional thermal energy within the battery cell. Further, thermal energy from one battery cell that has undergone cell thermal runaway can diffuse to adjacent battery cells, which in turn causes an increased temperature in the adjacent battery cells. In this way, a chain reaction of multiple failed battery cells in the energy storage system 100 may occur. Battery failure releases gas from the battery cells into the container 102 and increases the internal pressure of the sealed container 102. If the internal pressure increases above a predetermined threshold, the pressure relief valve is activated, preventing further failure of the energy storage system 100. However, the pressure relief valve provides a means for the energy storage system 100 shown in FIG. 1 to quickly and efficiently transfer heat energy from the battery cell arrays 114 to the outside of the container 102, thereby avoiding overheating scenarios. It is the only backup system to prevent.

As predicted by a person skilled in the art, the rate of heat energy transfer by conduction between two points is directly proportional to the difference in temperature between the two points and the thermal conductivity of the medium through which the transferred heat energy passes. The rate of heat energy transfer by convection from one medium to another is directly proportional to the difference in temperature between the two media as well as the surface area of the medium to which the heat energy is transferred. Because thermal energy always flows from a high temperature to a low temperature, the energy storage system 100 increases the transfer of heat energy from the battery cells to the external atmosphere surrounding the container 102 when the temperature of the battery cells is higher than the temperature of the external atmosphere. It is designed to let you do.

The energy storage system 100 is designed to efficiently increase the rate of conductive and convective heat energy transfer from battery cells to the exterior of the container 102 by using the subsystems, materials, and structural layout within the energy storage system 100. do. In general, efficient heat energy transfer is achieved according to the example shown in FIG. 1 by the following features. The battery cell arrays 114 are located in a fluid bath containing a fluid 108 having a high thermal conductivity that increases the transfer of thermal energy from the battery cell walls to the fluid 108. Fluid 108 is caused to circulate within container 102 to increase the rate of convective heat energy transfer from battery cells to fluid 108 and from fluid 108 to walls 104. The container walls 104 are of high thermal conductivity that increases the transfer of heat energy from the fluid 108 to the outer surface 112. The cooling fins 124 convectively transfer thermal energy from the container walls 104 and the outer side of the container walls 104 to conduct heat energy from the cooling fins 124 to the outer atmosphere of the container 102. It is located on the face 112.

In particular, as thermal energy is generated within the battery cells, the thermal energy is transferred to the battery walls causing an increased surface temperature of the battery walls. One of skill in the art would predict that the rate of heat energy transfer through the medium is directly proportional to the thermal conductivity of the medium. Thus, the temperature of the battery cells may be reduced, or the target temperature of the battery cells may be maintained by lowering the temperature of the fluid 108 below the target temperature of the battery cells. By immersing the battery cells in a fluid bath containing a fluid 108 that is at a temperature lower than the temperature of the battery cells and has a high thermoelectricity, thermal energy flows more rapidly from the battery walls to the fluid 108. Fluid 108 is beneficial compared to alternative air because air has a much lower thermal conductivity than fluid 108, and the fluid is generally four times greater than that of air. During operation of the energy storage system 100, if the fluid 108 is stagnant, the fluid 108 adjacent to the battery walls will cause the fluid 108 adjacent the inner surface to be transferred from the battery cells through the fluid 108. ) Is generally higher than the temperature. The addition of circulation of fluid 108 increases the rate of heat energy transfer by allowing the temperature difference between the battery cells and the inner surface 110 to occur through the fluid 108 at a relatively efficient rate. Greatly increase. The flow of fluid 108 along the fluid flow path 122 created by the recirculation pump 120 may be characterized by turbulent fluid flow, which means that the individual fluid particles are increased in shear mixing ( It further improves the rate of heat energy transfer in the fluid 108 as it exhibits an additional transverse motion causing shear mixing. Shear mixing causes a generally low temperature of the portion of fluid 108 adjacent to battery walls 104 at any given moment, which further increases the rate of heat energy transfer from battery walls 104 to fluid 108. Let it.

As the thermal energy is transferred to the fluid 108, the temperature of the fluid 108 tends to increase unless it is transferred from the fluid 108 at the same rate as the rate at which the thermal energy flows into the fluid 108. To avoid cell thermal runaway, the temperature of the fluid 108 should be kept below the maximum temperature. In order not to allow the temperature of the fluid 108 to rise, while maintaining a stable rate of heat energy transfer from the battery walls to the inner surface 110 through the fluid 108, the temperature of the inner surface 110 is ) Should be maintained at a temperature lower than the average temperature. The temperature of the inner surface 110 is maintained through the use of walls 104 and cooling fins 124 having high thermal conductivity. Since the wall 104 is made of a material having a high conductivity, the thermal energy generated by the battery cells and transferred to the inner surface 110 through the fluid 108 is lower than that of the fluid 108 in the outer surface 112. When maintained at temperature, it will quickly pass through the wall 104 to the exterior surface 112. The transfer of heat energy through the walls 104 will try to increase the temperature of the outer surface 112. However, the temperature of the outer surface 112 can be maintained through the use of cooling fins 124. As the thermal energy travels through the walls 104, the thermal energy then conducts conductively through the cooling fins 124 and finally dissipates from the surface of the cooling fins 124 into the surrounding air through convective thermal energy transfer. The large surface area of the cooling fins 124 enables rapid thermal energy transfer from the cooling fins 124 to the ambient air.

Thus, during operation of the energy storage system 100, the surface temperature of the cooling fins 124 is maintained at a temperature lower than the target temperature of the battery cells, and the total thermal energy from the battery cells to the ambient air surrounding the container 102 The delivery rate is increased. This improved thermal energy transfer rate from the battery walls 104 to the outside ambient air reduces the likelihood of cell thermal runaway and otherwise overheating of the battery cells 114 by more rapidly conducting thermal energy away from the battery cells. Help to let you do.

An alternative example of an energy storage system 100 is shown in FIG. 2 and includes a cooling system 200. The energy storage system 100 of FIG. 2 is similar to the energy storage system 100 of FIG. 1 and includes a container 102 having walls 104 having an outer surface 112 and an inner surface 110. . A pair of battery cell arrays 114, recirculation pump 120, sensors 138, data links 118, 116, and fluid 108 are located within container 102. A number of cooling fins 124 are located on the outer surface 112. The energy storage system 100 shown in FIG. 2 may have any number of battery cells, and is not limited to two battery cell arrays 114 as shown in FIG. 2. The container 102 is filled with a fluid 108, which is a fluid having high thermal conductivity and high electrical insulating properties. Recirculation pump 120 circulates fluid 108 in container 102 through and around battery cells.

The cooling system 200 includes a compressor 202, a condenser 204, an expansion valve 206, an evaporator 208, a cooling fan 210, and a refrigerant line 212. The configuration of the cooling system 200 shown in FIG. 2 is shown for illustrative purposes only, and is not necessarily intended to represent an actual physical layout of the cooling system. The cooling system 200 is a vapor compression cycle in which the refrigerant proceeds through the refrigerant line 212 through the four components of the compressor 202, condenser 204, expansion valve 206, and evaporator 208. Works. The refrigerant undergoes thermodynamic transformation during each phase of the vapor compression cycle. The refrigerant can be any of a variety of materials suitable for use in the cooling cycle, such as ammonia or methane. The refrigerant has a boiling point below the target temperature of the fluid 108 so that when the refrigerant enters the evaporator 208 the refrigerant must evaporate (or boil) during the evaporation phase.

Compressor 202 coincides with the compression phase of the vapor compression cycle and converts from vapor to superheated vapor. The refrigerant enters the compressor 202 as vapor through the refrigerant line 212. Compressor 202 applies mechanical work to increase the pressure and temperature of the refrigerant. During the compression process, the refrigerant is converted from steam to superheated steam because little or no thermal energy is transferred to or from the refrigerant. Compressor 202 can be any of a variety of compressors, such as a reciprocating compressor or a rotary reciprocator. Compressor 202 can be mounted at any suitable location outside container 102. However, it is desirable to place the compressor 202 at a location sufficiently away from the container 102 so as to minimize any interference with the compressor 202 from the thermal energy released from the container 102. Additionally, the compressor should be positioned close enough to the container 102 to minimize the length of the refrigerant line 212 and any corresponding efficiency losses.

Upon leaving the compressor 202, the refrigerant, which is superheated vapor, enters the condenser 204. In condenser 204, the refrigerant condenses and undergoes a phase change from superheated vapor to a liquid that is still hot and high pressure. Condenser 204 can be of any of a variety of condenser types known in the art. For example, the condenser 204 may include a heat exchanger section through which refrigerant travels through a number of snaked or looped condenser tubes 214. A number of condenser cooling fins 216 are attached to condenser tubes 214. The cooling fan 210 blows external cooling air through the heat exchanger section and directs cooling air over the condenser cooling fins 216. The cooling air convectively transfers thermal energy away from the surface of the condenser cooling fins 216 and creates a temperature difference, which transfers thermal energy conductively from the refrigerant through the condenser walls. The refrigerant is maintained in the condenser 204 at a substantially constant temperature and constant pressure. Although some temperature drop occurs while the superheated vapor reaches the liquid/vapor phase combination, little further temperature loss occurs during the condensation phase. Since the temperature and pressure of the refrigerant are maintained at a constant value (relatively high), as thermal energy flows from the refrigerant, the refrigerant phase changes from superheated vapor to liquid. The high temperature, high pressure liquid refrigerant then exits the condenser 204 and passes through the expansion valve 206.

The expansion valve 206 controls the circulation flow rate of the refrigerant through the refrigerant line 212 and slowly sends the refrigerant from the high-pressure environment to the low-pressure environment. The expansion valve 206 may be any of a variety of expansion valves known to control the flow of refrigerant into the evaporator, such as, for example, a thermostatic expansion valve or a capillary tube. When passing through the expansion valve 206, the high-pressure liquid refrigerant undergoes flash evaporation, and the refrigerant becomes a liquid-vapor mixture. During flash evaporation, very little heat energy transfer takes place, and the refrigerant cools rapidly as the temperature is largely directly proportional to the result of pressure and volume. The resulting temperature of the liquid-vapor refrigerant is preferably below the median temperature of the fluid 108 as the refrigerant continues along the refrigerant line 212 into the container 102 containing the evaporator 208.

Within the evaporator 208, a low pressure, low temperature refrigerant, which is a liquid/vapor mixture, is brought into sufficient contact with the fluid 108 for the refrigerant to absorb thermal energy from the fluid 108. Evaporator 208 may be any of a variety of evaporators suitable for use in cooling systems, such as a series of wound evaporator coils 218 through which refrigerant travels. The evaporator 208 is located directly within the container 102 and is immersed in the fluid 108. The walls of the evaporator coils 218 are preferably made of a material having a high thermal conductivity such as aluminum, for example, to maximize the rate of heat energy transfer between the fluid 108 and the refrigerant. Within the evaporator 208, the refrigerant undergoes thermal energy transfer with the fluid 108 through the conductive walls of the evaporator. Since the coolant temperature is lower than the average temperature of the fluid 108, thermal energy flows from the fluid 108 to the coolant. Because the refrigerant is at low pressure, the refrigerant can boil at low temperatures, and the refrigerant is vaporized. Once vaporized, the refrigerant continues to follow refrigerant line 212, exits container 102, and returns to the compressor to complete the cooling cycle.

The recirculation pump 120 in the container 102 works in conjunction with the cooling system 200 to increase the rate of heat energy transfer. By flowing the fluid 108 along the fluid flow path 122 shown in FIG. 2, the fluid 108 cannot be stagnant, so that the portion of the fluid 108 directly surrounding the evaporator coils 218 is largely It will be lower than the average temperature of the fluid 108. The recirculation pump 120 ensures that the fluid 108 flowing across the evaporator 208 is at a sufficiently high temperature to maximize the rate of heat energy transfer from the fluid 108 to the refrigerant traveling through the evaporator coils 218.

The refrigerant line 212 is configured to run through the wall 104 and is sealed when entering and leaving the wall 104. Seals may be any type of seals known in the art, such as, for example, polymer seals, O-rings, or compression seals. In this way, the interior of the container 102 is sealed to prevent external contaminants from entering the container 102, while allowing the refrigerant line 212 to enter and exit the container 102.

The cooling system 200 is a closed system such that the refrigerant cannot exit the cooling system. Accordingly, the refrigerant located in the refrigerant line 212 is sufficiently isolated from the fluid 108, so that the fluid 108 and the refrigerant cannot cross-contaminate each other. In this way, the refrigerant can be maintained or replaced via a portion of the refrigerant line 212 outside the container 102, while not causing contamination or damage to the inner seals of the container 102. Because the cooling system 200 requires energy to operate, to increase energy efficiency, the cooling system 200 stops when it is not necessary for the cooling system 200 to keep the temperature of the fluid 108 low enough. Can be. The cooling system 200 may be configured to communicate with a controller 128 (FIG. 1) that also communicates with sensors 138 such as a temperature sensor, a pressure sensor or a fluid level sensor. The controller 128 acts as a battery management system and may be configured to operate the cooling system 200 in response to signals received from the sensors 138, such as during high temperature or high pressure conditions. Similarly, the recirculation pump 120 can be activated as needed by the container 102 based on signals received from the sensors 138.

In an alternative embodiment of the energy storage system 100 (not shown), the cooling system 200 may be combined with a separate cooling system configured for the vehicle cab. It is known for a vehicle to have multiple evaporators in the same cooling circuit, while sharing a common refrigerant source and compressor. This avoids the need for multiple compressors adding unnecessary cost.

In another example of the energy storage system 100 shown in FIG. 3, the energy storage system 100 is a fluid loop 300 that carries fluid 108 through a heat exchanger 302 located outside the container 102. ). Heat exchanger 302 may include any of a variety of heat exchangers suitable for cooling a liquid, for example incorporating cooling fins and a cooling fan or any heat exchanger. The energy storage system 100 shown in FIG. 3 includes a single array of battery cells 114. However, in other examples, the energy storage system 100 may include one or more battery cell arrays 114 and battery cell arrays 114 in any of a variety of configurations. Fluid loop 300 carries fluid 108 outside of container 102 through heat exchanger 302. The first conveying line 304 conveys the fluid 108 through the fluid loop 300. The pump 306 flows the fluid through the first conveying line 304. The first conveying line 304 is fluidly connected to the container 102 at the outlet portal 308 and the inlet portal 310. The outlet portal 308 and the inlet portal 310 are fluidly connected with the interior of the container 102 so that the fluid 108 flows from the inside of the container 102 through the fluid delivery line 304. Can be sent outside. The inlet portal 310 and outlet portal 308 provide a sealed connection between the fluid delivery line 304 and the interior of the container 102. Seals may be any type of seals known in the art, such as, for example, polymer seals, O-rings, or compression seals.

Pump 306 flows fluid 108 through fluid delivery line 304 into heat exchanger 302. Heat exchanger 302 cools fluid 108 before fluid 108 advances back into container 102 through inlet portion 310. In this manner, the fluid 108 traveling from the container 102 through the outlet portal 308 has a higher temperature than the fluid 108 traveling through the inlet portal 310 and into the container 102. The cooled fluid 108 exiting the heat exchanger 302 enters the container 102 through the inlet portal 310 and flows along the fluid flow path 122 shown in FIG. 3. The fluid 108 is adjacent to the battery cell walls of the battery cell arrays 114, and the fluid 108 absorbs thermal energy from the battery cells. A portion of the heated fluid then enters the outlet portal 308 and continues along the fluid delivery line 304 into the heat exchanger 302, where the fluid 108 is once again cooled. In this way, the fluid loop 300 lowers the temperature of the fluid 108 and causes the battery cells to more rapidly flow thermal energy from the battery walls into the fluid 108 due to the increased temperature difference between the walls and the fluid 108. Helps lower their temperature.

It should be noted that although the previously described energy storage systems 100 include specific features, any combination of the above features shown in the examples may be used and are expected as part of the system described herein. For example, bulk head 106 and enclosure 126 may be used in connection with cooling system 200. Alternatively, cooling system 200 may be used in connection with fluid loop 300 and/or enclosure 126 in alternative examples. In this example, the cooling system 200 may have a fluid loop 300 as well as an evaporator 208 located within the container 102. As another example, the evaporator 208 may be located outside the container and may be used as a heat exchanger 302 or may be used in addition to the heat exchanger 302.

It should also be understood that, as the variable arrangement further enhances the transfer of heat energy from within the battery cells to the fluid 108, any of a variety of combinations of battery cell quantity and configuration may be used. It should be understood that various configurations of battery cell arrays 114 within container 102 can be envisaged, facilitating rapid transfer of heat energy from battery cells to fluid 108. For example, the battery cell arrays 114 may be configured in a diagonal shape for the example shown in FIG. 1.

While the present invention has been illustrated and described in detail in the drawings and the preceding description, these are considered illustrative and non-limiting in nature, and only preferred embodiments have been shown and described and are within the spirit of the invention defined by the following claims. It will be understood that all variations, equivalents and alterations need to be protected. All publications, patents, and patent applications cited in this specification are incorporated herein by reference as if specifically and individually indicated that each individual publication, patent, and patent application was incorporated by reference and presented in its entirety. .

Claims (31)

delete delete delete delete delete delete delete delete delete delete delete delete delete delete A battery cell array having one or more battery cells;
A container containing a liquid and having at least one wall, wherein the battery cell array is accommodated within the container and the liquid surrounds the battery cell array;
A recirculation pump located inside the container and immersed in the liquid;
One or more communication ports defined by the wall, each of the one or more communication ports extending outwardly away from the container, each of the one or more communication ports passing through the wall from the inside of the container to the outside of the container Having, the at least one communication port; And
A sensor within the container, the sensor electrically connected to the one or more communication ports and configured to measure physical parameters within the container; and
The battery cell array is electrically connected to one of the one or more communication ports by one of the one or more data links,
The recirculation pump is electrically connected to one of the one or more communication ports by one of the one or more data links, and the data link connected to the recirculation pump is at least partially immersed in the liquid. The method of claim 15,
Including an additional enclosure,
The enclosure has a receiving portion defined by a corresponding recess of the enclosure, the recess configured to receive the one or more communication ports. 17. The energy storage system of claim 16, wherein the receptacle comprises one or more terminals, the one or more communication ports comprises one or more contacts, and the one or more terminals are configured to be electrically connected to the one or more contacts. 18. The energy storage system of claim 17, wherein the one or more contacts are electrically connected to the one or more battery cells, and the one or more terminals are electrically connected to an electric motor generator. 18. The energy storage system of claim 17, wherein the one or more contacts include at least one contact electrically connected to the one or more data links, and the one or more data links are connected to the battery cell array. The method according to any one of claims 15 to 19,
Further comprising a compressor, a condenser, a metering device, and an evaporator coupled to each other to form a closed cooling circuit,
Wherein the evaporator is in fluid communication with the liquid inside the container and the condenser is in fluid communication with a secondary medium outside the container. 21. The energy storage system of claim 20, wherein the secondary medium is air and the condenser comprises condenser cooling fins and a condenser fan configured to direct a flow of air across the condenser cooling fins. delete The method of claim 15,
An inlet and outlet defined by the container and in fluid communication with the liquid in the container; And
A fluid conveying line coupled to the inlet and the outlet and defining a flow path outside the container,
The flow path is configured to pass the liquid from the outlet to the inlet. The method of claim 23,
Further comprising a heat exchanger located outside the container,
Wherein the fluid conveying line is coupled to the heat exchanger and the flow path passes through the heat exchanger before being sent to the inlet. 25. The energy storage system of claim 24, wherein the heat exchanger includes one or more cooling fins and a fan operable to direct a flow of air across the cooling fins. The method according to any one of claims 15 to 19,
cover; And
And a sealing member positioned between the cover and at least one wall of the container. 27. The energy storage system of claim 26, wherein the container is hermetically sealed. 20. The energy storage system of any of claims 15-19, wherein the sensor is configured to measure a battery temperature of the one or more battery cells. 16. The energy storage system of claim 15, wherein the sensor is configured to measure a liquid temperature of the liquid. The method according to any one of claims 15 to 19,
The energy storage system, further comprising one or more cooling fins on the outer surface of the container. The energy storage system according to any one of claims 15 to 19, wherein the liquid is electrically insulating and thermally conductive.

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